CS 405G: Introduction to Database Systems Lecture 1: Introduction

12/18/2015Jinze University of Kentucky2 Who am I? Instructor Jinze Liu Assistant professor in the department of Computer Science at UK Research area: Data mining and Bioinformatics Office: 235 Hardymon building

Topics for Today Topics What is a database? What is a database management system? Why take a database course? How to take the class? Preview of class contents 12/18/2015Jinze University of Kentucky3

Database Systems? Name a few! 12/18/2015Jinze University of Kentucky4

12/18/2015Jinze University of Kentucky5 Database Systems: Bank Systems

12/18/2015Jinze University of Kentucky6 Database Systems - Ecommerce

Database Systems: Clinical Databases 12/18/2015Jinze University of Kentucky7

12/18/2015Jinze University of Kentucky8 Database Systems: Genome Bank

12/18/2015Jinze University of Kentucky9 What is a Database? A database is an integrated collection of data. Data is a group of facts that can be recorded. Typically a database is used to model a real-world “enterprise” (or a miniworld) Entities (e.g., basketball teams, games) Relationships (e.g. UK’s basketball team beat ? yesterday)

12/18/2015Jinze University of Kentucky10 What is a Database Management System? A Database Management System (DBMS) is a collection of programs that enable users to create and maintain databases store, manage, and access data in a databases. Typically this term is used narrowly Relational databases with transactions E.g. Oracle, DB2, SQL Server Mostly because they predate other large repositories Also because of technical richness When we say DBMS in this class we will usually follow this convention But keep an open mind about applying the ideas!

12/18/2015Jinze University of Kentucky11 Main Characteristics of Databases Self-describing nature of a database system A DBMS catalog stores the description of the database. The description is called meta-data. Insulation between programs and data Allows changing data storage structures and operations without having to change the DBMS access Data Abstraction Use data model to hide storage details and present the users with a conceptual view of the database Support of multiple views of the data Each user may see a different view of the database, which describes only the data of interest to that user. Sharing of data and multi-user transaction processing

12/18/2015Jinze University of Kentucky12 Databases make these folks happy... End users in many fields Business, education, science, … DB application programmers Build data entry & analysis tools on top of DBMSs Build web services that run off DBMSs Database administrators (DBAs) Design logical/physical schemas Handle security and authorization Data availability, crash recovery Database tuning as needs evolve DBMS vendors, programmers Oracle, IBM, MS … …must understand how a DBMS works

12/18/2015Jinze University of Kentucky13 Search “Kentucky Basketball”

12/18/2015Jinze University of Kentucky14 Query “Kentucky Basketball”

12/18/2015Jinze University of Kentucky15 What: Is the WWW a DBMS? Fairly sophisticated search available Crawler indexes pages on the web Keyword-based search for pages But, currently data is mostly unstructured and untyped search only: can’t modify the data can’t get summaries, complex combinations of data few guarantees provided for freshness of data, consistency across data items, fault tolerance, … Individual web sites typically have a (relational) DBMS in the background to provide these functions.

12/18/2015Jinze University of Kentucky16 What: Is the WWW a DBMS? The picture is changing quickly Information Extraction to get structure data from unstructured data New standards e.g., XML, Semantic Web can help data modeling

12/18/2015Jinze University of Kentucky17 Thought Experiment 2: –You’re updating a file. –The power goes out. –Which changes survive? A) Yours B) Partner’sC) BothD) NeitherE) ??? A) AllB) NoneC) All Since Last SaveD) ??? What: Is a File System a DBMS? Thought Experiment 1: You and your project partner are editing the same file. You both save it at the same time. Whose changes survive? Q: How do you write programs over a subsystem when it promises you only “???” ? A: Very, very carefully!!

12/18/2015Jinze University of Kentucky18 Main Characteristics of Databases Self-describing nature of a database system A DBMS catalog stores the description of the database. The description is called meta-data. Insulation between programs and data Allows changing data storage structures and operations without having to change the DBMS access Data Abstraction Use data model to hide storage details and present the users with a conceptual view of the database Support of multiple views of the data Each user may see a different view of the database, which describes only the data of interest to that user. Sharing of data and multi-user transaction processing

12/18/2015Jinze University of Kentucky19 Advantages of a DBMS: a short list Controlling redundancy Restrict unauthorized access Providing persistent storage for program objects Providing storage structure for efficient query processing Providing backup and crash recovery …. And many many others that are going to be explored in this class

12/18/2015Jinze University of Kentucky20 Databases make these folks happy... End users in many fields Business, education, science, … DB application programmers Build data entry & analysis tools on top of DBMSs Build web services that run off DBMSs Database administrators (DBAs) Design logical/physical schemas Handle security and authorization Data availability, crash recovery Database tuning as needs evolve DBMS vendors, programmers Oracle, IBM, MS … …must understand how a DBMS works

12/18/2015Jinze University of Kentucky21 Current Commercial Outlook A major part of the software industry: Oracle, IBM, Microsoft also Sybase, Informix (now IBM), Teradata smaller players: java-based dbms, devices, OO, … Lots of related industries data warehouse, document management, storage, backup, reporting, business intelligence, ERP, CRM, app integration Traditional Relational DBMS products dominant and evolving adapted for extensibility (user-defined types), native XML support. Microsoft merger of file system/DB…?

12/18/2015Jinze University of Kentucky22 What database systems will we cover? We will try to be broad and touch upon Relational DBMS (e.g. Oracle, SQL Server, DB2, Postgres) “Semi-structured” DB systems (e.g. XML repositories like Xindice) Data mining: transfer data into knowledge! Starting point We assume you have used web search engines We assume you don’t know relational databases Yet they pioneered many of the key ideas So focus will be on relational DBMSs

12/18/2015Jinze University of Kentucky23 Why take this class? A. Database systems are at the core of CS B. They are incredibly important to society C. The topic is intellectually rich D. It isn’t that much work E. Looks good on your resume Let’s spend a little time on each of these

12/18/2015Jinze University of Kentucky24 Shift from computation to information True in corporate computing for years Web, p2p made this clear for personal computing Increasingly true of scientific computing Need for DB technology has exploded in the last few decades Corporate: retail swipe/clickstreams, “customer relationship mgmt”, “supply chain mgmt”, “data warehouses”, etc. Web: not just “documents”. Search engines, e-commerce, blogs, wikis, other “web services”. Scientific: digital libraries, genomics, satellite imagery, physical sensors, simulation data Personal: Music, photo, & video libraries. archives. File contents (“desktop search”). A. Database systems are the core of CS Why take this class?

12/18/2015Jinze University of Kentucky25 Why take this class? “Knowledge is power.” -- Sir Francis Bacon “With great power comes great responsibility.” -- SpiderMan’s Uncle Ben B. DBs are incredibly important to society Policy-makers should understand technological possibilities. Informed Technologists needed in public discourse on usage.

12/18/2015Jinze University of Kentucky26 representing information data modeling languages and systems for querying data complex queries & query semantics* over massive data sets concurrency control for data manipulation controlling concurrent access ensuring transactional semantics reliable data storage maintain data semantics even if you pull the plug data mining Let your data speak * semantics: the meaning or relationship of meanings of a sign or set of signs Why take this class? C. The topic is intellectually rich.

12/18/2015Jinze University of Kentucky27 Bad news: It is a lot of work. Good news: the course is front loaded Most of the hard work is in the first half of the semester Load balanced with most other classes Why take this class? D. It isn’t that much work.

12/18/2015Jinze University of Kentucky28 Yes, but why? This is not a course for: Oracle administrators IBM DB2 engine developers Though it’s useful for both! It is a course for well-educated computer scientists Database system concepts and techniques increasingly used “outside the box” Ask your friends at Microsoft, Yahoo!, Google, Apple, etc. Actually, they may or may not realize it! A rich understanding of these issues is a basic and (un?)fortunately unusual skill. Why take this class? E. Looks good on my resume.

About the course: Information Class web page is at Syllabus, homework, grading policy, etc. available from class web page Textbook Fundamentals of database systems Ramez Elmasri and Shamkant B. Navathe Can get it from the bookstore My Office Hours: 235 Hardymon building, Monday 2pm please include CS405G in the subject line for fast response Class mailing list Will send s to everyone once set up. Will be used for announcement/clarification of assignments/answering questions 12/18/201529

About the Course – Workload 6 homework assignments Including programming assignment Building blocks for your project 4 quizzes 1 Programming project Exams 1 Midterm & 1 Final Cheating policy: zero tolerance 12/18/201530

About the course: Project Programming projects have a practical, hands-on focus: A relational DBMS for a particular application Projects are to be done in teams of 2 Pick your partner ASAP! 12/18/201531

About the course: Grading Weights 6 Homework assignments 25% Project 20% Midterm exam 25% Final exam 25% Quizzes 5% More information is in the syllabus Final grade Late homework Will be penalized Academic mis-conduct You are expected to do the assignment independently Discussions if allowed should be acknowledged 12/18/201532

Next Class Database modeling The ER (Entity-Relationship) model Reading assignment Chapter 7.1, 7.2, 7.3. Any Questions? Any suggestions? 12/18/2015Jinze University of Kentucky33

12/18/2015Jinze University of Kentucky34 OS Support for Data Management Data can be stored in RAM This is what every programming language offers! RAM is fast, and random access Isn’t this heaven? Every OS includes a File System manages files on a magnetic disk allows open, read, seek, close on a file allows protections to be set on a file drawbacks relative to RAM?

12/18/2015Jinze University of Kentucky35 Database Management Systems What more could we want than a file system? simple, efficient ad hoc 1 queries concurrency control recovery benefits of good data modeling S.M.O.P. 2 ? Not really… as we’ll see this semester in fact, the OS often gets in the way! 1 ad hoc: formed or used for specific or immediate problems or needs 2 SMOP: Small Matter Of Programming